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排序方式: 共有143条查询结果,搜索用时 15 毫秒
81.
Jie Jian Dr. Roel Hammink Prof. Dr. Christine J. McKenzie Prof. Dr. F. Matthias Bickelhaupt Prof. Dr. Jordi Poater Prof. Dr. Jasmin Mecinović 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(9):e202104044
Boronic acids are Lewis acids that exist in equilibrium with boronate forms in aqueous solution. Here we experimentally and computationally investigated the Lewis acidity of 2,6-diarylphenylboronic acids; specially designed phenylboronic acids that possess two flanking aromatic rings with tunable aromatic character. Hammett analysis of 2,6-diarylphenylboronic acids reveals that their Lewis acidity remains unchanged upon the introduction of EWG/EDG at the distant para position of the flanking aromatic rings. Structural and computational studies demonstrate that polar-π interactions and solvation effects contribute to the stabilization of boronic acids and boronate forms by aromatic rings. Our physical-organic chemistry work highlights that boronic acids and boronates can be stabilized by aromatic systems, leading to an important molecular knowledge for rational design and development of boronic acid-based catalysts and inhibitors of biomedically important proteins. 相似文献
82.
Pit Boden Patrick Di Martino-Fumo Jasmin M. Busch Florian R. Rehak Sophie Steiger Dr. Olaf Fuhr Dr. Martin Nieger Daniel Volz Prof. Willem Klopper Prof. Stefan Bräse Prof. Markus Gerhards 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(17):5439-5452
To develop new and flexible CuI containing luminescent substances, we extend our previous investigations on two metal-centered species to four metal-centered complexes. These complexes could be a basis for designing new organic light-emitting diode (OLED) relevant species. Both the synthesis and in-depth spectroscopic analysis, combined with high-level theoretical calculations are presented on a series of tetranuclear CuI complexes with a halide containing Cu4X4 core (X=iodide, bromide or chloride) and two 2-(diphenylphosphino)pyridine bridging ligands with a methyl group in para (4-Me) or ortho (6-Me) position of the pyridine ring. The structure of the electronic ground state is characterized by X-ray diffraction, NMR, and IR spectroscopy with the support of theoretical calculations. In contrast to the para system, the complexes with ortho-substituted bridging ligands show a remarkable and reversible temperature-dependent dual phosphorescence. Here, we combine for the first time the luminescence thermochromism with time-resolved FTIR spectroscopy. Thus, we receive experimental data on the structures of the two triplet states involved in the luminescence thermochromism. The transient IR spectra of the underlying triplet metal/halide-to-ligand charge transfer (3M /XLCT) and cluster-centered (3CC) states were obtained and interpreted by comparison with calculated vibrational spectra. The systematic and significant dependence of the bridging halides was analyzed. 相似文献
83.
Frontispiece: Distinct Spacing Between Anionic Groups: An Essential Chemical Determinant for Achieving Thiophene‐Based Ligands to Distinguish β‐Amyloid or Tau Polymorphic Aggregates
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84.
Maria Sadia M. Rasul Jan Jasmin Shah 《International journal of environmental analytical chemistry》2013,93(14):1537-1556
In this work functionalised mesoporous silica spheres have been utilised for the simultaneous preconcentration of nickel and cobalt. The silica spheres (SiSPs) prepared by the sol-gel method were functionalised with sodium diethyldithiocarbamate (DDTC-SiSPs). They were characterised by SEM, TEM, XRD, FTIR, CHN and nitrogen adsorption. The adsorption efficiency of DDTC-SiSPs was examined by batch equilibrium technique. The DDTC-SiSPs showed 100% adsorption for Ni (II) and Co (II). The effect of changing variables such as pH, shaking time, sample volume, preconcentration factor, eluent type and volume were investigated so as to obtain maximum recovery with high selectivity over interfering ions. The maximum adsorption capacity was found to be 15.15 mg g?1 and 11.80 mg g?1 for Ni (II) and Co (II) respectively using DDTC-SiSPs. 100% recovery was achieved with 5 mL of 2 M HNO3. The maximum preconcentration factor was 400 and the 3σ limits of detection were 0.201 µg L?1 and 0.198 µg L?1 for Ni (II) and Co (II) respectively. Thermodynamic studies showed that adsorption of Ni (II) and Co (II) on DDTC-SiSPs is exothermic with enthalpy changes of –0.514 KJ mol?1 and –0.854 KJ mol?1 for Ni (II) and Co (II) respectively. The method was applied to the preconcentration and determination of Ni (II) and Co (II) from tap, river and sea water. 相似文献
85.
Lisa Milchram Anita Fischer Jasmin Huber Regina Soldo Daniela Sieghart Klemens Vierlinger Stephan Blüml Günter Steiner Andreas Weinhusel 《Molecules (Basel, Switzerland)》2022,27(4)
For the identification of antigenic protein biomarkers for rheumatoid arthritis (RA), we conducted IgG profiling on high density protein microarrays. Plasma IgG of 96 human samples (healthy controls, osteoarthritis, seropositive and seronegative RA, n = 24 each) and time-series plasma of a pristane-induced arthritis (PIA) rat model (n = 24 total) were probed on AIT’s 16k protein microarray. To investigate the analogy of underlying disease pathways, differential reactivity analysis was conducted. A total of n = 602 differentially reactive antigens (DIRAGs) at a significance cutoff of p < 0.05 were identified between seropositive and seronegative RA for the human samples. Correlation with the clinical disease activity index revealed an inverse correlation of antibodies against self-proteins found in pathways relevant for antigen presentation and immune regulation. The PIA model showed n = 1291 significant DIRAGs within acute disease. Significant DIRAGs for (I) seropositive, (II) seronegative and (III) PIA were subjected to the Reactome pathway browser which also revealed pathways relevant for antigen presentation and immune regulation; of these, seven overlapping pathways had high significance. We therefore conclude that the PIA model reflects the biological similarities of the disease pathogenesis. Our data show that protein array analysis can elucidate biological differences and pathways relevant in disease as well be a useful additional layer of omics information. 相似文献
86.
Tassilo M. F. Restle Jasmin V. Dums Dr. Gabriele Raudaschl-Sieber Prof. Dr. Thomas F. Fässler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(30):6812-6819
The lithium phosphidoaluminate Li9AlP4 represents a promising new compound with a high lithium ion mobility. This triggered the search for new members in the family of lithium phosphidotrielates, and the novel compounds Li3AlP2 and Li3GaP2, obtained directly from the elements via ball milling and subsequent annealing, are reported here. It was unexpectedly found through band structure calculations that Li3AlP2 and Li3GaP2 are direct band gap semiconductors with band gaps of 3.1 and 2.8 eV, respectively. Rietveld analyses reveal that both compounds crystallize isotypically in the orthorhombic space group Cmce (no. 64) with lattice parameters of a=11.5138(2), b=11.7634(2) and c=5.8202(1) Å for Li3AlP2, and a=11.5839(2), b=11.7809(2) and c=5.8129(2) Å for Li3GaP2. The crystal structures feature TrP4 (Tr=Al, Ga) corner- and edge-sharing tetrahedra, forming two-dimensional layers. The lithium atoms are located between and inside these layers. The crystal structures were confirmed by MAS-NMR spectroscopy. 相似文献
87.
88.
89.
M. Rasul Jan Farah Jabeen Jasmin Shah Fazal Mabood 《Journal of Thermal Analysis and Calorimetry》2010,101(1):303-308
An environment friendly method, thermal catalytic pyrolysis of used isobutyl isoprene rubber was investigated. In this method,
the used inner butyl tube rubbers were catalytically pyrolyzed into valuable hydrocarbons and carbon black. In this method,
the tube rubber was pyrolyzed both thermally (with out catalyst) and catalytically in a batch reactor under atmospheric pressure.
The effect of temperature, the amount of catalyst, and the reaction time on the yields of the pyrolyzed products were investigated.
Char yield decreased with increase of pyrolysis temperature while total gas and liquid yields increased. The liquid fraction
was obtained with boiling point up to 478 K. At optimum conditions, the liquid product was collected and analyzed for different
fuel properties. Typical analysis of the used isobutyl isoprene rubber oil for both the cases of parent and refluxed oil has
been performed. Phenols and carbonyls were quantitatively determined by spectrophotometric methods using folin-denis and phenyl
hydrazine reagents, respectively. The distillation data showed that ~100% of oil has boiling point <473 K which is the boiling
point for 80% of distilled product in commercial kerosene. Its specific gravity, viscosity, freezing point, Cetane number,
and diesel index were also within the limits of kerosene. 相似文献
90.
Josep L. Acero Sanchez Olivier Y. F. Henry Teresa Mairal Nadja Laddach Anders Nygren Siegfried Hauch Jasmin Fetisch Ciara K. O’Sullivan 《Analytical and bioanalytical chemistry》2010,397(6):2325-2334
An enzyme-linked oligonucleotide assay (ELONA) for quantification of mRNA expression of five genes involved in breast cancer,
extracted from isolated rare tumour cells and amplified by multiplex ligation-dependent probe amplification (MLPA) is presented.
In MLPA, a multiplex oligonucleotide ligation assay is combined with a PCR reaction in which all ligation products are amplified
by use of a single primer pair. Biotinylated probes complementary to each of the target sequences were immobilised on the
surface of a streptavidin-coated microtitre plate and exposed to single-stranded MLPA products. A universal reporting probe
sequence modified with horseradish peroxidase (URP–HRP) and complementary to a universal primer used during the MLPA step
was further added to the surface-bound duplex as a reporter probe. Simultaneous addition of anchoring probe and target, followed
by addition of reporter probe, rather than sequential addition, was achieved with no significant effect on sensitivity and
limits of detection, but considerably reduced the required assay time. Detection limits as low as 20 pmol L−1, with an overall assay time of 95 min could be achieved with negligible cross-reactivity between probes and non-specific
targets present in the MLPA-PCR product. The same MLPA-PCR product was analysed using capillary electrophoresis, the technique
typically used for analysis of MLPA products, and good correlation was observed. The assay presented is easy to carry out,
relatively inexpensive, rapid, does not require sophisticated instrumentation, and enables quantitative analysis, making it
very promising for the analysis of MLPA products. 相似文献